Robinson Helicopter CO R66 accident near Wikieup, Arizona, June 23, 2016
On June 23, 2016 at about 9:25 pm local time, a 2011 Robinson Helicopter CO R66, registered N117TW, was destroyed in an accident during enroute (cruise) near Wikieup, Arizona. It was a positioning flight under general aviation rules (Part 91). 2 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An encounter with turbulence due to updrafts and/or dust devils that resulted in mast bumping and an in-flight break-up.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 23, 2016 · about 9:25 pm local time
- Place
- Wikieup, Arizona · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson Helicopter CO R66, built 2011
- Registration
- N117TW · no longer on the register · serial 0042
- Damage
- Destroyed
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot and the pilot-rated passenger departed on a cross-country positioning flight. The helicopter was reported overdue when it did not arrive at the destination, and the wreckage was located the following morning. There were no witnesses to the accident, no recorded radar data, and no recorded radio transmissions from the pilot. Examination of the wreckage revealed no evidence of any preexisting anomalies that would have precluded normal operation of the helicopter. There was evidence that a mast bumping event had occurred and that the main rotor blades had contacted the airframe, which resulted in an in-flight break-up. There was no recorded information available that could be used to determine the helicopter's airspeed, altitude, or the pilot's control inputs. A weather study indicated that conditions were conducive to the development of significant updrafts or thermals of rising air and dust devils, and people near the accident site reported that there were numerous dust devils in the area. It is likely that the helicopter encountered turbulence due to updrafts and/or dust devils, and the pilot lost control of the helicopter, which resulted in mast bumping.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Turbulence encounter during enroute (cruise)
- Mast bumping during enroute (cruise) defining event
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Main rotor system › Main rotor mast/swashplate › Related operating info
- cause Environmental issues › Conditions/weather/phenomena › Turbulence › Convective turbulence › Effect on operation
- cause Environmental issues › Conditions/weather/phenomena › Turbulence › Terrain induced turbulence › Effect on operation
Pilot
- Certificate: airline transport pilot, flight instructor
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: helicopter; instructor: instrument airplane; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 8,000 hours in all; 10 in the last 90 days; 3 in the last 30 days
- Last flight review: December 10, 2015
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: fatal
Pilot-Rated Passenger
- Certificate: flight instructor, commercial pilot, private
- Ratings: single-engine land; instructor: helicopter; instructor: instrument helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 5,220 hours in all; 101 in this make and model; 89 in the last 90 days; 42 in the last 30 days; 3,769 as pilot in command
- Last flight review: February 22, 2016
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 662 hours
- Last inspection: 100-hour inspection, February 16, 2016
- Maximum gross weight: 2,700 lb
- Seats: 5
- Landing gear: fixed
- Engine: Rolls Royce 250-C300A1 (turboshaft); 694 hours total
- Fire on the ground
The flight
- Departed from: PRC Prescott AZ at 8:38 pm
- Destination: RAL Riverside CA
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 190° at 17 knots, gusting 22
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 109°F (43°C), dew point 27°F (-3°C)
- Altimeter: 29.79 inHg
- Observation at 9:35 pm from KHII, 43 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
12 documents, released by the NTSB on November 9, 2017. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Weather Study | PDF, 23 pages | View Download |
| 2 | Personal Electronic Device - Specialist's Factual Report | PDF, 2 pages | View Download |
| 3 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 4 | Weather Witness Statements | PDF, 4 pages | View Download |
| 5 | NTSB on Site Examination Notes | PDF, 17 pages | View Download |
| 6 | NTSB Airframe and Engine Follow-up Exam Report | PDF, 18 pages | View Download |
| 7 | Spot Tracker Information | PDF, 5 pages | View Download |
| 8 | Statement of Party Representatives to NTSB Investigation | PDF, 3 pages | View Download |
| 9 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
| 10 | Evidence Control Form (iPad) | PDF, 1 page | View Download |
| 11 | Toxicological Report (Pilot) | PDF, 1 page | View Download |
| 12 | Toxicological Report (Pilot-rated Passenger) | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.